System Components / Upgrading and Repairing PCs

In these days of commodity parts and component pricing, building your own system from scratch is no longer the daunting process it once was. Every component necessary to build a PC system is available off the shelf at competitive pricing. In many cases, the system you build can use the same or even better components than the top name-brand systems.

There are, however, some cautions to heed. The main thing to note is that you rarely save money when building your own system; purchasing a complete system from a mail-order vendor or mass merchandiser is almost always less expensive. The reason for this is simple: Most system vendors who build systems to order use many, if not all, of the same components you can use when building your own system. The difference is that they buy these components in quantity and receive a much larger discount than you can by purchasing only one of a particular item.

In addition, you pay only one shipping and handling charge when you purchase a complete system instead of the multiple shipping charges you pay when you purchase separate components. In fact, the shipping, handling, and phone charges from ordering all the separate parts needed to build a PC through the mail often add up to $100 or more. This cost rises if you encounter problems with any of the components and have to make additional calls or send improper or malfunctioning parts back for replacement. Many companies charge restocking fees if you purchase something and then determine you don't need it or can't use it.

If you purchase parts locally, you typically must pay the additional state sales tax, as well as the higher prices usually associated with retail store sales.

Then there is the included software. Although I can sometimes come close in price to a commercial system when building my own from scratch, the bundled software really adds value to the commercial system. An upgrade copy of Windows XP costs $100 or more, and most commercial systems also include Microsoft Office or other applications as well. Many commercial systems come with $250–$500 or more worth of software, depending on what they include.

It is clear that the reasons for building a system from scratch often have less to do with saving money and more to do with the experience you gain and the results you achieve. In the end, you have a custom system that contains the exact components and features you have selected. Most of the time when you buy a preconfigured system, you have to compromise in some way. For example, you might get the video adapter you want, but you would prefer a different make or model of motherboard. By building your own system, you can select the exact components you want and build the ultimate system for your needs. The experience is also very rewarding. You know exactly how your system is constructed and configured because you have done it yourself. This makes future support and installation of additional accessories much easier.

Another benefit of building your own system is that you are guaranteed a nonproprietary system that will be easily upgradeable in the future. Of course, if you have been reading the book up to this point, you already know everything you need to ensure any preassembled systems you purchase would be nonproprietary and, therefore, upgradeable and repairable in the future.

You might be able to save some money using components from your current system when building your new system. You might have recently upgraded your hard drive and optical drive in an attempt to extend the life of your current computer. In most cases, you can take those components with you to the new system. For example, if you bought a 120GB hard drive and a DVD+RW drive for your old system, you can move them to a newer system.

The good news is that your monitor, keyboard, mouse, and storage devices—as well as most AGP video cards and all PCI-based add-on cards—from your old system will work in your new system. The bad news is that most newer systems require a memory type different from an older system and some AGP cards might not work in newer motherboards.

So, if you are interested in a rewarding experience, want a customized and fully upgradeable system that is not exactly the same as that offered by any vendor, are able to take on all system repair and troubleshooting tasks, want to save some money by reusing some of the components from your current system, and are not in a hurry, building your own PC might be the way to go.

On the other hand, if you are interested in getting a PC with the most value for the best price, want one-stop support for in-warranty repairs and technical problems, and need an operational system quickly, building your own system should be avoided. In that case, you should consider purchasing a system from a name-brand vendor. Also, if you are unable to provide self-support or will not be upgrading the system, you might consider an extended warranty. An extended warranty essentially prevents you from doing any upgrades to the system because an upgrade is not covered and, in some cases, can even invalidate the warranty on the rest of the system. If you do plan to upgrade your system after a year or so of use, you should avoid purchasing any extended warranties.

This chapter details the components necessary to assemble your own system, explains the assembly procedures, and lists some recommendations for components and their sources.

Case and Power Supply

The case and power supply are typically sold as a unit, although some vendors do sell them separately. There are a multitude of designs from which to choose, usually dependent on the motherboard form factor you want to use, the number of drive bays available, and whether the system is desktop or floor mounted. There are cases with extra fans for cooling (recommended), air filters on the air inlets to keep out the dust, removable side panels, or motherboard trays; cases that require no tools for assembly, rack-mounted versions, and more. For most custom-built systems, an ATX mid-tower case and power supply is the recommended choice. Cases designed for the older Baby-AT motherboard form factor are still available, but the ATX architecture offers considerable improvements. The size and shape of the case, power supply, and even the motherboard are called the form factor. The most popular case form factors are as follows:

Cases that take ATX boards are found mostly in the full-tower, mini-tower, and desktop form factors, although some vendors now use flex-ATX motherboards in their low-profile systems. When deciding which type of case to purchase, you should consider where you will place your computer. Will it be on a desk? Or is it more feasible to put the system on the floor and just have the monitor, keyboard, and mouse on the desk? The amount of space you have available for the computer can affect other purchasing decisions, such as the length of the monitor, keyboard, and mouse cables.

Of the choices listed, it is recommended that you avoid the low-profile systems. Designed primarily for use in business environments, these Slimline systems have a smaller footprint, meaning that they take up less space on your desk than the typical desktop computer and usually are not designed with expansion in mind. These cases require a special type of highly integrated motherboard. Older versions used the Low Profile or LPX board. The low-profile version of the ATX form factor is called the NLX. LPX and NLX motherboards often have virtually everything built in, including video, sound, and even network adapters. Flex-ATX motherboards are used in some of the latest small form factor systems.

LPX and NLX motherboards do not have any normal adapter slots. Instead, all the expansion slots are mounted on an adapter board called a riser card, which plugs into a special slot on the motherboard. Standard PCI or ISA adapter cards then plug sideways into the riser card (parallel to the motherboard), making expansion difficult and somewhat limited. In addition, the small size of the case makes working inside the machine difficult. Some designs force you to remove some components to gain access to others, making system maintenance inconvenient. A flex-ATX motherboard can have one or two slots, although some of these systems have no slots at all.

See "Motherboard Form Factors," p. 196.

Most newer cases accept ATX-style boards, which have become the standard for Athlon XP and Pentium 4–based systems. If you are interested in the most flexible type of case and power supply that will support the widest variety of future upgrades, I recommend sticking with the ATX-style cases and power supplies.

Note

Generally, any ATX case, motherboard, and power supply of sufficient wattage for your equipment can be put together to form the basis of a new system. However, there are two major exceptions you need to know about:

Many Dell systems built from 1996 through 2000 use nonstandard motherboards and power supplies with what appears to be a standard ATX power supply physical connector; however, the pinout and voltage levels have changed. If you mix a nonstandard Dell motherboard and a standard ATX power supply, or a standard ATX motherboard and a nonstandard Dell power supply, you will destroy the power supply and possibly your motherboard as well! If you want to upgrade newer Dell systems, you must either buy Dell-compatible power supplies for use with the Dell motherboard or replace both Dell components with standard ATX components. See Chapter 21, "Power Supply and Chassis/Case," for more details. Many of Dell's newer systems also use nonstandard power supplies and motherboards, but these are more obvious in that they do not use standard connectors either, which means a standard ATX motherboard or power supply will not physically plug in. This makes an upgrade difficult or impossible, but at least you won't blow up any hardware in the process.
Intel Pentium 4 and AMD Athlon CPUs require heavy heatsinks and fans for cooling. Be sure to use a heatsink designed for your particular processor, and make sure it is properly installed. These high-powered systems also require an ATX12V power supply, which has an additional 12V connector for the motherboard-based CPU voltage regulators. ATX12V adapters are available to convert standard ATX power supplies, but in general you should upgrade to an ATX12V supply that has upgraded internal circuitry and wiring to handle the additional 12V power required.

Whether you choose a desktop or one of the tower cases is really a matter of personal preference and system location. Most people feel that the tower systems are roomier and easier to work on, and the full-sized tower cases have lots of bays for various storage devices. Tower cases typically have enough bays to hold floppy drives, multiple hard disk drives, CD-ROM drives, tape drives, and anything else you might want to install. However, some of the desktop cases can have as much room as the towers, particularly the mini- or mid-tower models. In fact, a tower case is sometimes considered a desktop case turned sideways or vice versa. Some cases are convertible—that is, they can be used in either a desktop or tower orientation.

Tip

Mini-tower or micro-tower systems are an exception to the roomy tower case rule. These systems normally use the Micro-ATX motherboard and might have only two or three drive bays. These systems are almost as difficult to work on as a Slimline system.

When it comes to the power supply, the most important consideration is how many devices you plan to install in the system and how much power they require. Chapter 21 describes the process for calculating the power your system hardware requires and selecting an appropriate power supply for your needs.

See "Power-Use Calculations," p. 1160.

When you build your own system, you should always keep upgradeability and repairability in mind. A properly designed custom PC should last you far longer than an off-the-shelf model because you can more easily add or replace components. When choosing a case and power supply, leave yourself some room for expansion, on the assumption that you will eventually want to install an additional hard drive or some other new device that appears on the market that you can't live without. To be specific, be sure you have at least two empty internal drive bays and choose a higher output power supply than you need for your current equipment, so it won't be over-taxed when additional components are added later.

Processor

Both Intel and AMD sell processors through two primary channels or methods. They are referred to as boxed and OEM.

A boxed processor and an OEM processor might have the same specifications, but they are packaged differently, include different supplemental components, and have different warranties. Even though the boxed processors are sometimes also called retail processors, they are technically not intended to be sold in the normal retail channel. Both boxed and OEM processors are technically wholesale items and, as such, can be purchased from Intel or AMD only by signing up as a dealer with them and meeting their requirements to achieve and maintain dealer status. After you are registered as an Intel or AMD dealer, you can purchase boxed processors directly from them.

OEM processors are sold only to major accounts that purchase hundreds of chips at a time. Although neither the boxed nor OEM processors are intended to be sold in the retail channel, after Intel or AMD sells them to one of their dealers, that dealer is free to resell the chips as he chooses. Therefore, an individual can purchase either boxed or OEM processors from many sources.

The most obvious difference between the boxed and OEM processors is the physical packaging. It could be argued that both technically come in boxes, but the Intel or AMD boxed processors come individually packaged in a colorful shrink-wrapped box that includes the processor, the heatsink and fan, installation instructions, a certificate of authenticity, warranty paperwork, as well as an "Intel inside" or "AMD instead" sticker that is supposed to be affixed to the front of the system chassis (see Figure 22.1).

On the other hand, OEM processors come in a much larger box with 10 trays containing 10 processors each, or 100 processors in total. No heatsinks, fans, installation instructions, warranties, or other paperwork are included. These are purchased in large quantities by the major system manufacturers.

A boxed processor generally includes a 3-year warranty direct with the processor manufacturer. So, if the chip fails within 3 years of purchase, the end user can contact Intel or AMD directly and they will replace the chip. OEM processors have no warranty with the manufacturer (Intel or AMD); however, the company from which you purchased it will likely offer a 30- or 90-day warranty. The warranty length and the way in which it is administered are entirely up to the dealer from which you purchased the chip, which could be a problem if, for example, that dealer has gone out of business.

Boxed processors also include a high-quality, manufacturer-supplied heatsink and cooling fan. Typically, the cooling system provided with a boxed processor is designed to work under worst-case thermal environments and is a very high-quality and heavy-duty unit. When you think about it, it wouldn't serve Intel or AMD to provide cheap heatsinks and fans on a processor they are warranting for 3 years!

OEM processors, on the other hand, include no heatsink or fan, but the dealer from which you purchase the processor will likely provide one. Unfortunately, these are often of very uneven quality and performance, up to the whims of the particular dealer you are using. With only a 30- or 90-day warranty, it doesn't matter as much if the manufacturer skimps on the heatsink because, if the chip fails beyond the short warranty period, the company isn't obligated to replace it. If you purchase an OEM processor with a motherboard, most dealers install the processor into the motherboard and provide a single warranty covering both items.

The motherboards you consider should have one of the following processor sockets or slots:

The following slot and socket types also can be purchased but are not compatible with the latest CPU models and will limit your future processor upgrade options:

Because the motherboard you choose dictates or limits your choice in processor, you should choose your processor first. These days, the choice of processors runs the gamut from the Intel Celeron on the low end to the AMD Athlon XP, Athlon 64, and Intel Pentium 4 on the high end. For more information on these and all other processors, see Chapter 3, "Microprocessor Types and Specifications."

See "Processor Socket and Slot Types," p. 85.

Depending on the type of motherboard you select, there might be jumpers on the motherboard to set for processor type and speed. It also might have jumpers to control the voltage supplied to the processor. Typically, older Socket 7 or Super7 boards have jumpers for motherboard bus speed, CPU multiplier, and CPU voltage settings. If you purchase this type of board, be sure you get these settings correct; otherwise, the system won't run properly. In a worst-case situation, you can damage the processor with too high a voltage setting, for example.

All modern processor sockets handle these settings automatically, so there is little danger of incorrect settings. Even so, several boards have overrides for the automatic settings, which can be useful for those intending to hotrod or overclock their processors. Most of these boards use the BIOS Setup to control these overrides, so no jumpers or switches need to be set.

Motherboard

Several compatible form factors are used for motherboards. The form factor refers to the physical dimensions and size of the board and dictates into which type of case the board will fit. The types of compatible industry-standard motherboard form factors generally available for system builders are as follows:

The ATX motherboard design is far and away the most popular and best motherboard design for most people building their own systems today. It is also the most common. ATX is an open architecture that improves on the older Baby-AT design in many ways that affect other components of the computer, such as the case and power supply. An ATX motherboard has the same basic dimensions as a Baby-AT; however, it is rotated 90° in the case from the standard Baby-AT orientation. This places the expansion slots parallel to the short side of the board, allowing more space for other components without interfering with expansion boards.

Components that produce large amounts of heat, such as the CPU and memory, are located next to the power supply for better cooling and easier access to the processor and memory sockets. ATX motherboards feature a high degree of port integration, but unlike Baby-AT motherboards, all ATX external ports are built into the motherboard and are mounted to one side of the expansion slots. You won't need to use the clumsy and easily damaged or disconnected ribbon cables used by Baby-AT motherboards to carry mouse, serial, parallel, or USB ports to the rear of the system.

The ATX-style power supply features a redesigned, single-keyed (foolproof!) connector that can't be plugged in backward or off-center. Plugging power supply connectors backward or off-center by a pin is easy to do in the Baby-AT design, and the result is catastrophic: The motherboard is destroyed the moment the power is turned on. This is impossible with the shrouded and keyed ATX power connector. This power supply provides the motherboard with the 3.3V current used by many of the newer CPUs and other components. ATX power supplies are also designed to support the advanced power-management features now found in system BIOSs and operating systems.

The micro-ATX form factor is a further development of the ATX design, intended for use in lower-cost systems. The micro-ATX architecture is backward-compatible with ATX and specifies a motherboard that is physically smaller, as the name implies. These smaller motherboards can be installed in standard ATX cases or in smaller cases specifically designed for the micro-ATX boards.

Slimline systems have used several form factors over the years. The LPX form factor was popular until the late 1990s, but the lack of standardization and the low-profile case used by most versions made it a very poor choice for system builders. Because of the differences among systems with LPX motherboards, upgrading the motherboard on a system that uses an LPX motherboard is very difficult. The NLX form factor is another open standard Intel developed, with features comparable to the ATX but defining a Slimline-style case and motherboard arrangement. Systems based on the NLX standard should not experience the compatibility problems of LPX-based systems, but the inherent problems of the Low-Profile design remain. These types of form factors are popular with corporate clients and novice consumers because of the systems' small footprint and the "everything-on-the-motherboard" design. However, replacement NLX motherboards are relatively scarce compared to the abundance of ATX and micro-ATX motherboards on the market.

Mini-ITX motherboards are a semi-proprietary design sold as a unit with one of several low-power-consumption VIA processors. Because the fastest C3 E-series processor used with Mini-ITX motherboards is just 1GHz, the mini-ITX form factor is unsuitable for high-performance systems. However, because it features a PCI expansion slot and integrates almost all common I/O ports (even USB 2.0 and IEEE-1394a in the latest models), it's a good choice for a slimline system in which cooling and noise can be a problem. Many vendors now support Mini-ITX motherboards with low-profile cases and power supplies. However, Mini-ITX is not a true industry standard because a complete specification is not available. Instead, it is just a marketing tool for VIA Technologies to sell some of its processors, chipsets, and motherboards; therefore, a limited number of motherboards, cases, and power supplies work with this format. Mini-ITX has a potential for many interchange problems, especially with items such as power supplies. Unless having the smallest possible system is worth sacrificing upgradeability, repairability, and performance, you should choose a system based on the ATX standard instead.

Note

For more information on all the motherboard form factors, see Chapter 4, "Motherboards and Buses." You can also find the reference standard documents detailing the modern form factors at the Desktop Form Factors Web site: http://www.formfactors.org.

You also need to verify that the motherboard supports both the processor you plan to install initially as well as the processor you might upgrade to in the future. For example, if you choose a Socket A motherboard, you should verify that it supports Athlon XP processors with 333MHz FSB, including the Athlon 2800+ and 3000+. If you choose a Socket 478 motherboard, you should verify that it supports HT Technology (hyper-threading), a feature of the 3.06GHz and faster Pentium 4 processors. In some cases, a BIOS upgrade might be necessary.

In addition to processor support and form factor, you should consider several other features when selecting a motherboard. The following sections examine each feature.

Chipsets

Aside from the processor, the main component on a motherboard is called the chipset. This usually is a set of one to five chips that contains the main motherboard circuits. These chipsets replace the 150 or more distinct components that were used in the original IBM AT systems and enable a motherboard designer to easily create a functional system from just a few parts. The chipset contains all the motherboard circuitry except the processor and memory in most systems.

Because the chipset really is the motherboard, the chipset used in a given motherboard has a profound effect on the performance of the board. It dictates all the performance parameters and limitations of the board, such as memory size and speed, processor types and speeds, supported buses and their speeds, and more. If you plan to incorporate technologies such as the Accelerated Graphics Port (AGP) or the Universal Serial Bus (USB) into your system, you must ensure that your motherboard has a chipset that supports these features.

Because chipsets are constantly being introduced and improved over time, I can't list all of them and their functions here; however, you will find a detailed description of many of them in Chapter 4. Several popular high-performance chipsets are on the market today. The best of these offer support for double data rate synchronous DRAM (DDR SDRAM) or Rambus DRAM (RDRAM) memory, PCI and AGP 4x or faster buses, Advanced Configuration and Power Interface (ACPI), and USB 2.0 and Ultra-DMA 100 ATA (IDE) support.

See "Chipsets," p. 229.

See "Motherboard Selection Criteria (Knowing What to Look For)," p. 359.

Clearly, the selection of a chipset must be based largely on the processor you choose and the additional components you intend to install in the computer.

However, no matter which chipset you look for, I recommend checking for the following supported features:

Most of the better chipsets on the market today should have these features and more. If you are intent on building the ultimate PC (at least by this week's standards), you also should consider the fastest processors available. Be sure not to waste your investment on the most capable processor by using a chipset that doesn't fully exploit its capabilities.

When you are designing your system, carefully consider the number and type of expansion cards you intend to install. Then, ensure that the motherboard you select has the correct number of slots and that they are of the correct bus type for your peripherals (ISA, PCI, and AGP). Because many newer boards don't have ISA slots, it might be time to get rid of any ISA boards you have and replace them with more capable PCI versions.

When you buy a motherboard, I highly recommend you contact the chipset manufacturer and obtain the documentation (usually called the data book) for your particular chipset. This explains how the memory and cache controllers, as well as many other devices in the system, operate. This documentation should also describe the Advanced Chipset Setup functions in your system's Setup program. With this information, you might be able to fine-tune the motherboard configuration by altering the chipset features. Because chipsets are frequently discontinued and replaced with newer models, don't wait too long to get the chipset documentation because most manufacturers make it available only for chips currently in production.

Note

One interesting fact about chipsets is that in the volume that the motherboard manufacturers purchase them, the chipsets usually cost about $40 each. If you have an older motherboard that needs repair, you usually can't purchase the chipsets because they aren't stocked by the manufacturer after they are discontinued. Not to mention that most chipsets feature surface mounting with ball grid array (BGA) packages that are extremely difficult to manually remove and replace. The low-cost chipset is one of the reasons motherboards have become disposable items that are rarely, if ever, repaired.

BIOS

Another important feature on the motherboard is the basic input/output system (BIOS). This is also called the ROM BIOS because the code is stored in a read-only memory (ROM) chip. There are several things to look for here. One is that the BIOS is supplied by one of the major BIOS manufacturers, such as AMI (American Megatrends International), Phoenix, Award (owned by Phoenix), or Microid Research. Also, be sure that the BIOS is contained in a special type of reprogrammable chip called a Flash ROM or EEPROM (electrically erasable programmable read-only memory). This enables you to download BIOS updates from the manufacturer and, using a program it supplies, easily update the code in your BIOS. If you do not have the Flash ROM or EEPROM type, you must physically replace the chip if an update is required.

See "Upgrading the BIOS," p. 384.

Virtually all motherboards built in the last few years include a BIOS with support for the Plug and Play (PnP) specification. This makes installing new cards, especially PnP cards, much easier. PnP automates the installation and uses special software built into the BIOS and the operating system (such as Windows 9x/Me and Windows 2000/XP) to automatically configure adapter cards and resolve adapter resource conflicts.

You also need to verify that the BIOS supports both the processor you plan to install initially and the processor you might upgrade to in the future. If the motherboard and chipset can handle a new processor but the BIOS cannot, a BIOS upgrade can be used to provide proper support.

Note

For more information on PnP, see "Plug and Play BIOS" in Chapter 5, "BIOS." Also, an exhaustive listing of PnP device IDs can be found in the Technical Reference section of the DVD included with this book.

Memory

Older systems had L2 cache memory on the motherboard, but for almost all newer systems starting with the Pentium II, this cache is now a part of the processor. The few remaining Socket 7 or Super7 motherboards do still include cache onboard, and it is normally soldered in and not removable or upgradeable.

See "Cache Memory: SRAM," p. 425.

For Pentium II/III/4; Celeron systems; and AMD's Athlon, Athlon XP, and Duron systems, no additional L2 memory is necessary because the processors have the cache memory integrated into the processor package.

Main memory typically is installed in the form of dual inline memory modules (DIMMs) or Rambus inline memory modules (RIMMs). Four physical types of main memory modules are used in PC systems today, with several variations of each. The four main types are as follows:

The 168-pin SDRAM DIMMs are found only in older or lower-end systems today. DIMMs have become popular because they are 64 bits wide and can be used as a single bank on a Pentium or higher-class processor that has a 64-bit external data bus. Some of the newest and fastest systems using the Pentium 4 processor use the RDRAM RIMMs, which offer significant performance gains over standard SDRAM.

Double data rate (DDR) SDRAM memory is a newer variation on SDRAM in which data is transferred twice as quickly, and it is the most common type of memory used in recent systems. DDR2 DIMMs are coming in new systems during 2004, and the RDRAM RIMMs are being phased out, with virtually no new supporting chipset or motherboard designs forthcoming. Note that although both DDR DIMMs and RDRAM RIMMs use 184-pin connectors, their pin configurations are completely different and the modules are not interchangeable.

See "Physical RAM Capacity and Organization," p. 457.

See "DDR SDRAM," p. 435.

A 64-bit Pentium class system requires two 72-pin SIMMs (32 bits wide each) or a single 168-pin DIMM (64 bits wide) to make a single bank.

Memory modules can include an extra bit for each 8 for parity checking or ECC use. If ECC is important to you, be sure your chipset (and motherboard) supports ECC before purchasing the more expensive ECC modules.

See "Parity and ECC," p. 464.

Another thing to watch out for is the type of metal on the memory module contacts, especially on motherboards using SIMMs. They are available with either tin- or gold-plated contacts. Although it might seem that gold-plated contacts are better (they are), you should not use them in all systems. You should instead always match the type of plating on the module contacts to what is also used on the socket contacts. In other words, if the motherboard SIMM, DIMM, or RIMM sockets have tin-plated contacts, you must use modules with tin-plated contacts. Most motherboards with SIMM sockets used tin-plated ones, requiring tin-plated SIMMs, whereas most DIMM and RIMM sockets are gold-plated, requiring gold-plated DIMMs and RIMMs.

If you mix dissimilar metals (tin with gold), corrosion on the tin side is rapidly accelerated and tiny electrical currents are generated. The combination of the corrosion and tiny currents causes havoc, and several types of memory problems and errors can occur. In some systems, I have observed that everything seems fine for about a year, during which the corrosion develops. After that, random memory errors result. Removing and cleaning the memory module and socket contacts postpones the problem for another year, and then the problems return. How would you like this problem if you have 100 or more systems to support? Of course, you can avoid these problems if you insist on using SIMMs with contacts whose metal matches the metal found in the sockets in which they will be installed.

See "Gold Versus Tin," p. 461.

I/O Ports

Most motherboards today have built-in I/O ports. If these ports are not built in, they must be supplied via a plug-in expansion board that, unfortunately, wastes an expansion slot. The following ports might be included in any new system you assemble:

Some motherboards lack the serial, parallel, keyboard, and mouse ports (referred to as legacy ports), instead relying on USB for those connections. You might want to avoid "legacy-free" motherboards if you still use peripherals with those types of connections. Many motherboards feature the optional integrated video and sound interfaces, especially micro-ATX motherboards.

All the integrated ports are supported either directly by the motherboard chipset or by an additional Super I/O chip and additional interface components. Adding the optional video and sound interfaces directly to the motherboard saves both money and the use of an expansion slot, especially important in the less expensive systems sold today.

If these devices are not present on the motherboard, various Super I/O or multi-I/O boards that implement all these ports are available. Again, most of the newer versions of these boards use a single-chip implementation because it is cheaper and more reliable.

See "Super I/O Chips," p. 304.

It has become an increasingly popular practice in recent years (especially in Slimline-style systems) to integrate other standard computer functions into the motherboard design, such as video, sound, and even network adapters. The advantages of this practice include freeing up expansion slots that would normally be occupied by separate adapter cards and saving money. The price difference between a motherboard with integrated video and sound and one without would be far less than the cost of good-quality sound and video cards.

The drawback, of course, is that you have little or no choice about the features or quality of the integrated adapters. Integrated components such as these are nearly always of serviceable quality, but they certainly do not push the performance envelope of higher-end expansion cards. Most people who decide to build a system themselves do so because they want optimum performance from every component, which you do not get from integrated video and sound.

Buying a motherboard with integrated adapters, however, does not preclude you from adding expansion devices of the same type. You usually can install a video or sound card into a system with an integrated sound or video adapter without major problems, except that the additional cost of the integrated component is wasted. You also might encounter difficulties with the automated hardware detection routines in operating systems such as Windows 9x/Me/2000/XP detecting the wrong adapter in your system, but you can remedy this by manually identifying the expansion card to the OS. If you want the convenience of integrated video but want to maintain the option of installing a faster AGP (4x or 8x) video card later, look for systems that provide both integrated video and an AGP slot.

See "Integrated Video/Motherboard Chipsets," p. 863, "Intel 845 Family," p. 274, and "Intel 865 Family," p. 276.

If four or more USB ports exist, they often are split among two buses, with one set of connections on the back of the board and another set as a pin-header connector on the motherboard. A cable then plugs into this connector, enabling you to route the second USB bus port to the front of the PC case. Most newer cases have provisions for front-mounted USB ports in this manner, which makes temporarily connecting devices such as digital cameras or MP3 players for transferring files easier. Even though USB 2.0 support is increasingly common, some systems use a separate USB 2.0 support chip; therefore, some USB ports on such systems support only the older USB 1.1 standard. Also, you might need to enable USB 2.0 support in the system BIOS and load USB 2.0 drivers before USB 2.0 ports will support USB 2.0 devices at top speed.

Note that if your motherboard has integrated devices such as video and sound, you must go into the BIOS Setup to disable these devices if you want to add a card-based replacement device. Check your BIOS Setup menus for an Enable/Disable setting for any integrated devices.

A trend with some newer low-cost systems is the complete elimination of the integrated ports supported by the Super I/O chip or the Super I/O features of recent South Bridge chips. These are called legacy-free PCs and lack any serial ports, parallel ports, and standard keyboard and mouse connections. All external expansion must be done via the USB ports. This means your keyboard, mouse, printer, external modem, and so on must be of the USB type. Some so-called "legacy-free" systems still have PS/2 mouse and keyboard ports but have eliminated serial and parallel ports.

Floppy Disk and Removable Drives

Since the advent of the CD-RW, the floppy disk drive has largely been relegated to a minor role as an alternative system boot device. Usually, today's systems are equipped with a 1.44MB 3 1/2'' drive. All systems today are capable of booting from CD, making CD-R (or especially CD-RW discs) a useful high-capacity replacement for floppy or Zip drives.

For additional removable storage, I recommend a CD-RW (CD-rewriteable) or DVD+RW drive over the Zip or even LS-120 formats, particularly if you have a limited amount of money. These are now relatively inexpensive, and the media is low priced as well. A CD-RW drive can also write on even more inexpensive CD-R media, and DVD+RW drives can use less expensive DVD+R media. This provides an easy way to back up or archive up to 700MB (using CD-R/RW) or 4.7GB (using DVD+R/RW) of data.

If you can budget around $100–$150, you can purchase combo CD-RW/DVD-ROM drives that also support DVD movie playback. For about $300, you can get a rewriteable DVD+RW drive, which can read and write CD-R/RW discs as well. The versatility of a DVD+RW drive is tremendous because it enables you to work with virtually any type of optical media and lets you store up to 4.7GB on a single rewriteable or recordable DVD.

Hard Disk Drives

Your system also needs at least one hard disk drive. In most cases, a drive with a minimum capacity of 40GB is recommended, although in some cases you can get away with less for a low-end configuration. High-end systems should have drives of 80GB or higher. One of the cardinal rules of computer shopping is that you can never have too much storage. Buy as much as you can afford, and you'll almost certainly end up filling it anyway.

Tip

If you are an Internet user, one informal method of estimating how much disk space you will need is to go by the speed of your Internet connection. If you have a high-speed link, such as that provided by a DSL connection, a cable modem, or a LAN, you will find that the ease of downloading large amounts of data fills disk drives amazingly quickly. I would recommend at least an 80GB hard drive in these cases. In addition, a removable storage system with a large capacity, such as a CD-RW drive, is also a good idea.

Note that Windows 95 does not support any drives larger than 32GB. You should upgrade to at least Windows 98 or 2000, although at this point I recommend taking the leap to Windows XP.

The most popular hard drive interface for desktop systems is ATA (IDE), although SCSI is preferable for use with multitasking OSs. ATA generally offers greater performance for single-drive installations, but SCSI is better for use with two or more drives or with multitasking operating systems, such as Windows 95/98/Me and NT/2000/XP. This is because of the greater intelligence in the SCSI interface, which removes some of the I/O processing burden from the system's CPU. This is especially important if you are using Windows NT or Windows 2000 in a server role, where it supports multiple users and much heavier file access. The SCSI interface is also more versatile than ATA; it can handle either 7 or 15 devices, including scanners, tape drives, optical drives, hard drives, and removable-media drives.

Some of the newest motherboards now feature RAID-compatible ATA interfaces. These enable you to install two identical IDE drives (a pair of 80GB drives, for example) and treat them as a single very large and very fast 160GB hard drive.

The newest motherboards now feature Serial ATA (SATA) interfaces, some of which are also RAID compatible. Although the SATA drive interface is faster than the fastest ATA interface on the market (ATA-133), real-world SATA drive performance is currently on par with ATA drive performance. However, if your motherboard supports SATA, the smaller cable size used for data and the promise of higher performance in the future can still make using SATA drives a better choice.

Most all systems have USB 2.0, and more and more systems have IEEE-1394a (FireWire 400) built in to the motherboard or added as PCI expansion cards. Although FireWire 400 and USB 2.0–based drives have performance similar to ATA drives and can be moved from system to system, they are not recommended as primary drives. However, they can be used for additional portable storage or system backup.

See "ATA RAID," p. 541, and "Serial ATA," p. 536.

Note

In most cases, a system's ATA adapter is integrated into the motherboard. With SCSI, this is much less common. Although you sometimes can purchase a motherboard with an integrated SCSI adapter, most of these motherboards are designed for use in servers. Thus, you are more likely to have to purchase a separate SCSI host adapter and install it into one of your system's expansion slots. Almost all SCSI adapters on the market use the PCI expansion slot. Good-quality SCSI host adapters are considerably more complex than are ATA adapters and are therefore more expensive. Be sure to consider this additional expense and the need for an additional slot when deciding on a hard drive interface for your system.

See "How to Reliably Record CDs," p. 768.

See "SCSI Versus ATA (IDE)," p. 573.

Several brands of high-quality hard disk drives are available from which to choose, and most offer similar performance within their price and capacity categories. In fact, you might notice that the capacities and specifications of the various ATA and SCSI drives certain manufacturers offer are remarkably similar. This is because a single drive assembly is manufactured for use with both interfaces. The same ATA drive, for example, with the addition of a SCSI interface chip on the logic board, becomes a SCSI drive, often at a substantially higher price.

Optical Drives

An optical drive is considered a mandatory item in any PC you construct these days. This is because virtually all software is now distributed on CD-ROM, and some newer titles are on DVD. DVD drives can read CD-ROMs as well as DVD-ROMs, so they are more flexible. Systems can now even boot from CD-ROM drives as long as the system BIOS provides the proper support.

DVD-ROM is a high-density data storage format that uses a CD-size disc to store a great deal more data than a CD-ROM—from 4.7GB to 17GB, depending on the format. These drives can read standard CD-ROMs and audio CDs, as well as the higher-capacity DVD data and video discs.

See "DVD," p. 712.

At one time, rewriteable CD and DVD drives were extremely expensive, but today, I recommend that you start with a rewriteable drive. I recommend a minimum of a CD-RW drive with 40x read, 40x write, and 12x rewrite connected to the ATA interface on the motherboard. This results in the best possible performance with the minimum amount of hassle. Combo CD-RW/DVD-ROM drives are available that add DVD read capabilities as fast as 12x to the CD-RW features. For the ultimate combination of features, I recommend DVD+R/RW drives as the best overall optical drives on the market. The DVD+R/RW format is the fastest and most compatible, has the most features, and is designed to support the integrated EasyWrite capability (also called Mt. Rainier) coming in the next Windows release in 2005. This will finally allow the replacement of the floppy drive because CDs and DVDs will be usable for burning right out of the box, with no format time (formatting is done in the background) and no extra packet writing software needed.

If you need compatibility with DVD-R/RW media, I recommend a combo DVD+-R/RW drive such as those available from Sony. If you don't need to use the DVD-R/RW media, a standard DVD+R/RW drive is the best choice.

Burning your own CDs or DVDs can be a convenient and relatively inexpensive data storage method. Drives advertised as RW handle both RW (rewriteable) and R (record once) media. Note, however, that many older CD-ROM drives can't read CD-RW media (drives labeled as MultiRead can read CD-RW media), whereas virtually all drives can read CD-R discs.

Tip

For the highest reliability when using CD-RW drives, be sure your drive incorporates one of the forms of buffer underrun protection, such as BURN-proof, JustLink, or Waste-Proof. This prevents you from making coasters (unusable discs) when burning CDs.

Input Devices

Obviously, your system needs a keyboard and some type of pointing device, such as a mouse. Different people prefer different types of keyboards, and the "feel" of one type can vary considerably from other types. If possible, I suggest you try a variety of keyboards until you find the type that suits you best. I prefer a stiff action with tactile feedback myself, but others prefer a lighter, quieter touch.

Because two types of keyboard connectors are found in systems today as well as the multipurpose USB port, be sure that the keyboard you purchase matches the connector on your motherboard. The original 5-pin DIN and newer 6-pin mini-DIN keyboard connectors are electrically compatible, enabling you to adapt either type of keyboard connector to either type of keyboard. The newest keyboard interface is USB, driven by the widespread availability of the USB connector and the rise of legacy-free PCs that have only USB ports.

As with any USB device, you must have support in the operating system for USB, and in the case of USB keyboards, your system BIOS must support a function called Legacy USB or USB Keyboard and Mouse if you want to use the USB keyboard outside the Windows graphical user interface. Most recent BIOSs have this feature. However, to enable you to use your USB keyboard on both new and older systems, I recommend you look for a model that also supports the traditional keyboard ports. This type of keyboard usually ships with a USB port and a 6-pin mini-DIN adapter.

If you prefer a wireless keyboard, be sure to choose one that uses RF (radio) instead of IR (infrared) signaling, and get one that can use a single transceiver for both the keyboard and mouse. RF signaling might use either short-range proprietary frequencies or the industry-standard Bluetooth wireless network. Bluetooth devices are preferable if you want to use the keyboard or mouse with a wide variety of devices or at distances greater than 6 feet or so from the system.

See "Keyboards," p. 980.

See "Keyboard Technology," p. 986.

The same selection concept also applies to mice or other pointing devices; a number of choices are available that suit different individuals. Try several before deciding on the type you want.

Although many recent systems no longer have built-in mouse ports, you should get a mouse that can be used with both the PS/2 port (so named because it was introduced with the IBM PS/2 systems of 1987 and beyond) and the newer USB port. I recommend dual-mode mice that work with either type of system. In addition, you can even choose from cordless versions that use proprietary short-range signals or Bluetooth. If you are using a wireless keyboard and mouse, select models that can share the same transceiver.

Tip

You might be tempted to skimp on your keyboard and mouse to save a few dollars. Don't! You do all your interacting with your new PC through these devices, and cheap ones make their presence known every time you use your system. I insist on high-quality mechanical switch–type keyboards on all my systems.

The Universal Serial Bus (USB) is rendering the standard I/O ports on the PC obsolete. Essentially, USB brings PnP support to external peripherals by enabling you to plug up to 127 devices into a single port supporting data transfer rates up to 12Mbps with USB 1.1 or 480Mbps (60MBps) with USB 2.0. Typically, you plug a USB hub into a port integrated into the motherboard and then plug other devices into that. Virtually all current motherboards support USB, and you can update a USB 1.1–only system to USB 2.0 with an add-on card.

See "USB and IEEE-1394 (i.Link or FireWire)," p. 946.

There are virtually no limits to the types of devices available for USB. Modems, keyboards, mice, CD-ROM drives, speakers, joysticks, hard drives, tape drives, floppy drives, scanners, cameras, MP3 players, and printers are just some of the devices available. However, before you start buying all USB peripherals for your new system, be aware that performance problems can occur with some devices if used on a single bus, and sometimes compatibility problems can occur as well. USB 2.0 (also called High-Speed USB) solves these problems, so you should be sure that any new systems you buy or build include USB 2.0 ports.

See "USB Keyboards," p. 983.

Video Card and Display

You need a video adapter and a monitor or display to complete your system. Numerous choices are available in this area, but the most important piece of advice I have to give is to choose a good monitor. The display is your main interface to the system and can be the cause of many hours of either pain or pleasure, depending on which monitor you choose.

I usually recommend a minimum of a 17'' CRT display these days (equivalent to a 15'' LCD display). Anything smaller can't acceptably display a 1,024x768 pixel resolution. If you opt for a 15'' or smaller CRT display, you might find that the maximum tolerable resolution is 800x600. This might be confusing because many 15'' monitors are capable of displaying 1,024x768 resolution or even higher, but the characters and features are so small onscreen at that resolution that excessive eyestrain and headaches are often the result; the display often is blurry when a monitor is run at its maximum resolution. If you spend a lot of time in front of your system and want to work in the higher screen resolutions, a 17'' CRT display should be considered mandatory. If you can afford it, I recommend a 19'' CRT display; they work even better at the higher resolutions and have come down in price considerably from previous years. Look for CRT displays with lower dot-pitch (0.28dpi or less), which indicates the size and spacing of dots in the CRT mask. Lower means higher resolution and a clearer picture.

If your desk space is limited and you can afford it, consider the wide variety of flat-screen LCD panels now available (a 15'' LCD panel is about equal in viewable area to a 17'' CRT). In most cases, they attach to the normal VGA analog port, but the most current models work with the DVI connector available on some of the newest video cards. LCD panels are an excellent choice if you always use the native resolution (typically 1024x768 on 15'' displays or 1280x1024 on 17'' displays), but if you need to change resolutions (for previewing Web page designs or game playing), CRTs are better.

Your video card and monitor should be compatible in terms of refresh rate. The minimum refresh rate for a solid, nonflickering CRT display is 70Hz–72Hz (the higher, the better). If your new video card can display 16 million colors at a resolution of 1,024x768 and a refresh rate of 76Hz, but your monitor's maximum refresh rate at 1,024x768 is 56Hz, you can't use the video card to its maximum potential. Configuring a video adapter to deliver signals the monitor can't support is one of the few software configuration processes that can physically damage the system hardware. Pushing a monitor beyond its capabilities can cause it irreparable harm. Note that LCD displays don't flicker, regardless of the refresh rate.

Video adapters in recent years have become standardized on the accelerated graphics port (AGP) interface, although many older systems used PCI-based video cards. You might need to use a PCI video card if you are adding a secondary video adapter to your system to run a second monitor and prefer not to replace your primary video card. Windows 98, Me, 2000, and XP support this feature, and it can be very useful for some applications. To save a slot in your system, you can also use a dual-display card in your AGP slot. Replacing your single-display video card with a dual-display card is the best option today because most of the latest video cards in all performance ranges now support dual displays. You also avoid driver, BIOS, and hardware conflicts that can result from trying to get two cards to coexist in the same system.

If you are into gaming, you need one of the high-performance 3D video cards currently available. Modern games are very video-intensive, so be sure to check the Web sites, manuals, and even game boxes for the games you play to see which cards they recommend. Although early 3D cards connected to the standard 2D graphics card, this design is now obsolete. High-performance 3D cards based on chipsets from NVIDIA and ATI provide both fast 2D graphics and excellent 3D performance.

See "Accelerated Graphics Port," p. 333.

See "3D Graphics Accelerators," p. 880.

If you are adding a video card to a newly constructed system, the video card should be inserted into the AGP slot. Most current motherboards support AGP 4x, AGP Pro, or AGP 8x. I recommend video cards with at least 32MB of memory if you don't play 3D games or are a casual gamer; 64MB or more is a necessity if you play a lot of 3D games. Look for TV-out if you want to attach your system to a big-screen TV for presentations or watching DVD movies. If you want to add TV viewing and recording features to your system, consider a video card with video capture and editing features such as the All-in-Wonder series from ATI, the 8500 and 9700 Pro versions, or NVIDIA-based systems featuring the Personal Cinema USB TV tuner.

If you are installing a newer AGP video card as an upgrade to your current system, you can remove the current video card and replace it with any video card that supports the motherboard's AGP standard. You can also replace an existing PCI video card with another PCI video card if there is no AGP slot, but you should consider a motherboard upgrade instead to provide an AGP slot for faster video.

Many motherboards with onboard video also have an AGP slot; if your motherboard has one, you can insert an AGP card into this slot. The onboard video should be automatically disabled in most cases.

If the motherboard has only PCI slots, you might want to consider upgrading to a motherboard that has an AGP slot instead.

If you are replacing an existing video card, be sure to check the chipset on the video card against the list of video card chipsets provided in the section "3D Chipsets" in Chapter 15, "Video Hardware." You should avoid chipsets marked as OLD if you are looking for acceptable performance and support for the latest versions of Windows.

Audio Hardware

You need a motherboard with integrated audio or a sound card and a set of external speakers for any system that you want to be multimedia capable. Most systems today, even those without integrated video, now feature integrated audio, but you might prefer to add a high-quality sound card if you want the best possible sound quality for DVD playback or audio capture and editing. Almost any motherboard-integrated audio system and sound card on the market today are compatible with both the Creative Labs Sound Blaster series and Windows DirectX and other sound APIs. Although a few stores still stock ISA sound cards, for best performance, I recommend you get a PCI-based sound card. There can be some problems with support for older DOS-based games with some of the new cards, but most of these issues have been addressed by special drivers for the newer cards.

Speakers designed for use with PCs range from tiny, underpowered devices to large audiophile systems. Many of the top manufacturers of stereo speakers now produce speaker systems for PCs. Some include subwoofers or even a full Dolby 5.1, 6.1, or 7.1 surround sound implementation.

Accessories

Apart from the major components, you need several other accessories to complete your system. These are the small parts that can make the assembly process a pleasure or a chore. If you are purchasing your system components from mail-order sources, you should make a complete list of all the parts you need, right down to the last cable and screw, and be sure you have everything before you begin the assembly process. It is excruciating to have to wait several days with a half-assembled system for the delivery of a forgotten part.

Heatsinks/Cooling Fans

Most of today's faster processors produce a lot of heat, and this heat has to be dissipated so your system doesn't operate intermittently or even fail completely. Heatsinks are available in two main types: passive and active.

Passive heatsinks are simply finned chunks of metal (usually aluminum) that are clipped or glued to the top of the processor. They act as a radiator and, in effect, give the processor more surface area to dissipate the heat. Active heatsinks are required by many processors today because of their higher capacity and smaller space requirements. Often you have no control over which heatsink you use because it comes already attached to the processor. If you have to attach it yourself, you should use a thermal transfer grease or sticky tape to fill any air gaps between the heatsink and the processor. This allows for maximum heat transfer and the best efficiency.

An active heatsink includes a built-in fan. These can offer greater cooling capacity than the passive types, and some processors—especially "boxed" processors from Intel and AMD—are sold with the heatsink and fan included. OEM processors don't include a heatsink from the processor manufacturer, but most vendors who sell them add an aftermarket heatsink and fan to the package; often, aftermarket heatsinks and fans provide significantly better cooling than those shipped with boxed processors. Thus, an OEM processor is a better candidate for overclocking. Note that all modern heatsinks require a thermal interface material (usually grease or paste) be applied to the base of the heatsink before installation.

Note

The ATX form factor motherboards and chassis are designed to improve system cooling. These systems move the processor and memory near the power supply for better cooling. They often feature secondary case-mounted cooling fans for extra insurance. Note that many processors today come with the heatsink integrated as a part of the unit, often an active type with a high-quality ball-bearing cooling fan built in.

Another consideration for cooling is with the case. The fan in the power supply and optionally one on the CPU heatsink often are not enough for a modern high-performance system. I recommend you get a case that includes at least one additional cooling fan. This is typically mounted in the front of the chassis, taking air in from the front and directing it over the motherboard; it often is hidden behind the card support slots used for full-length expansion cards. Some cases include extra fans near the drive bays for cooling the drives as well.

If you are upgrading an existing system, several companies make fan assemblies that insert into a drive bay for additional cooling. They take the place of a 5 1/4'' drive and take air in through the front bezel, directing it back into the case. Bay-mounted fans are an especially good idea if you are using the 10,000rpm or faster SCSI drives on the market because they run extremely hot. There are even fan assemblies mounted on cards that blow air out the rear of the case. Keep in mind that it is best to keep the interior of the PC below 100°F; anything over 110° dramatically reduces component life and leads to stability problems.

Cables

PC systems need many different cables to hook up everything. These can include power cables or adapters, disk drive cables, internal or external CD-ROM cables, and many others. Frequently, the motherboard includes the cables for any of the internal ports, such as floppy or hard drives. Other external devices you purchase come with included cables, but in some cases, they aren't supplied. The Vendor List on the DVD contains contact information for several cable and small parts suppliers that can get you the cables or other parts you need to complete your system.

Another advantage of the ATX motherboard form factor is that these boards feature externally accessible I/O connectors directly mounted to the rear of the board. This eliminates the rat's nest of cables found in the older Baby-AT form factor systems and also makes the ATX system a little cheaper and more reliable.

If you build your system using all OEM (what the industry calls white box) components, be aware that these sometimes don't include the accessories, such as cables and additional documentation, that you would get with a boxed-retail version of the same component.

Hardware

You might need screws, standoffs, mounting rails (if your case requires them), and other miscellaneous hardware to assemble your system. Most of these parts are included with the case or your other system components. This is especially true of any card or disk drive brackets or screws. When you purchase a component such as a hard drive, some vendors offer you the option of purchasing the bare drive or a kit containing the required cables and mounting hardware for the device. Most of the time bare drives don't include any additional hardware, but you might not need it anyway if the mounting hardware comes with your case. Even so, spending the few additional dollars for the complete drive kit is rarely a waste of money. Even if you're left with some extra bits and pieces after assembling your system, they will probably come in handy someday.

In situations in which you need other hardware not included with your system components, you can consult the Vendor List for suppliers of small parts and hardware necessary to get your system operational.

Upgrading and Repairing PCs